Telephone-exchange system and apparatus



(No Model.) I 4"Sheets-Sheet 1. F. SHAW & W. A. OHILDS.

TELEPHONE EXCHANGE SYSTEM AND APPARATUS.- No. 278,613. Patented May 29,1883.

WITNESSES 'IJV R N. PETERS PhulmLilhognpMn wauhingtan. I16.

(No Model.)

4 Sheets-Sheej; 2. I F. SHAW & W. A. CHILD S. V

TELEPHONE EXGHANGE SYSTEM AND APPARATUS.

I N VEJVTOR j ws-4K New I Attorney u. PEIEIS. mum s, M (1 (No Model.) 4 Sheets-Sheet 3. F. SHAW & W. A. OHILDS. TELEPHONE EXCHANGE SYSTEM AND APPARATUS.

Dvmivrozz' ".dttorney Patented May 29,1883.

u. rains mwww-nw WM WITNESSES (No Model) 7 4 Sheets-Sheet 4. P. SHAW & WpA. OHILDS. TELEPHONE EXCHANGE SYSTEM AND APPARATUS.

@ kaw INVEJVTOR Patented May 29,1883.

WITNESSE Y N. PEYERS. Phomum n mr. Walhingion. DJ;

FRANK suaw,

UNITED STATES PATENT @rrron.

OF NEW YORK, N-. Y., AND WILLIAM A. OHILDS', 0F ENGLE- WOOD, NEW JERSEY.

TELEPHONE-EXCHANGE SYSTEM AND APPARATUS.

SPECIFICATION forming part of Letters Patent No. 278,613, dated. May 29, 1883.

Application filed January 19,1883. (No model.)

To all whom it may concern Be it known that we, FRANK SHAW, of New York city, and WILLIAM A. OHILDS, of Eaglewood, New Jersey, have invented new and useful Improvements in Telephone-Exchange Ap-v paratus and Systems, of which the following is a specification.

Our invention relates to improvements in telephone switch boards or tables and other necessary apparatus for receiving orders for connections and disconnections from subscribers, and for giving and receiving orders for trunk-line connections and disconnections, and also for making such connections and discon nections, the former being made between subscribers wires of one group or central office and the latter between the subscribers wires .of any two groups or central offices through trunk-lines for subscribers use between such central offices.

The objects ofour invention are to save space and expenseby reducing the size ot'the switchboard; to save in the number and expense of operators; to save confusion,delay,repetition, and errors, and secure quiet, promptness, and

, accuracy, and at the same time to-put the in vertical section, with part of the bottom B,

rod R, and cord D, in section, with four plugs,

f Gr,in perspective; Fig.3,arod, cord, spring, and

plug in perspective; Fig. 4, a switch in front view; Fig. 5, a plan of" two groups of central offices connected together; and Fig. 6, the same, with the addition of the apparatus and lines of two subscribers stations connected with central office No. 1 and two more connect ed with central-office No. 2.

In each of the groups Nos. 1 and 2, Fig. 5,

the outfits of three subscribers operatorsO and the outfit of one trunk-operator O are shown. In Fig.6 only one of the outfits of operators and six (6) feet high-for less than one thousand Wires and subscribers, before which the operators rush back and forth in more or loss con fusion to perform their duties. In another system desks having about fifty (50) wiresand apparatus for connection are provided for each operator, and increased as the subscribers increase. In still another system duplicate switch-boards are provided for each additional I switch operator connected with extension lines in order to keep these operators'separate, prevent confusion, and enable operators in charge of any particular section of-a switchboard to make connections with subscribers lines, belonging normally to other sections. In each of these systems, and in all others so far as we .know, the operators, whether the board be entirely upright or placed upon a desk and in part upright, are placed uponone side only of the switch-board, the board being 1 arranged, disposed, and adapted forthis purpose; andwhere more than one operator opcrates either of these boards he or theymust do so from a position beside the firstoperator, the result of which is inevitable interference of each operator withevery other inv the necessary manipulations.

In our invention the apparatus is arranged in the form pf a table, around which the operators may'sit, having the whole top of the table within the reach of each operator, one or more. Fig.1 shows the top part of such a table. four hundred small metallic tubes, standingclosely together, like so many candle-moldsin a frame. This case is made as follows: At top and bottom it has a board or plank say thirtytwo (32) inches long, eight (8 inches 0 in Fig. l is a case containing, say, 9

i insane wide, and two inches thickperforat'ed with l the subscribers offices there are, upon the four hundred (400) holessay of seven-sixteenths(-, inch diameter. These holes are disposed in four sections, each having ten (10) holeson aside, niakingone hundred (100) holes in a section,four hundred (400) in all, and threequarters of an inch from center to center. These holes receive tubes T,-whichare twentysix inches long and extend between the. two planks B B, and, say, half-way through the same, at the ends.' Each hole in the bottom plank, B, has the end of a subscribers wire inserted therein, as shown at W, Fig. 2. This wire is secured by simply driving the lower -end of the tube into the hole, the result of which is that each tube becomes practically an extension of the particular subscribers wire inserted in that particular hole. The bottom holes are made preferably of the same size as the bottom ends of the tubes T, so as to drive solidly and hold the wire W firmly, and at the same time make and maintain electrical contact. The top holes are made ot'su'ch size as to allow thetubes to pass easily from above and through them into the lower holes. The boards B and Bniay be made from two or more layers or pieces of wood secured together in any usual way;

P P P P are plates of metal provided with holes made continuous with those in B. These plates are ground-plates, havingeach agroundconnection, and they. may be made in sub-sec tions, it convenience requires. These plates P rest upon the top of the board B with sufficient space between their under sides andthe upper ends of the tubes T T to insure insulation therefrom.

Figs.2 and 3 show a rod, It, and flexible conducting-cord D, with plug G, terminating the same. The rod R is cut away at top to receive a flexible flat spring, S, preferably made of German silver. The rod B, being dropped into a tube, T, from above, will fall by its own weight within the tube T, drawing the cord D after it until the broad part of the plug Gr rests upon the plate P, to which the tube T belongs. The spring S is so attached to the rod R as to project beyond its surface and press with sufticient force against the in:

side of the tube T to effect electrical contact.

Consequently when a plug G rests upon a .plate P a round-connection is established from the subscribers wires.

Each one of the four hundred tubes T has its rod R, cord D,

and plug G, and every one of the four hundred wires being so connected, atmospheric electricity will be conducted to the ground safely, and all the'other advantages incident to a normal groundconnection will .be secured. Among these advantages are the-escape of induced currents of a battery-current from a cross or accident, thereby preventing. the ringing' of the bell in subscribers office, and also other advantages arising from having the subscribers private lines electrically directly connectedwith a common plate" or conductor in the central office. Between these plates and to number each row of holes in the plates P,

for the guidance of the operators.

P P P are simply connecting-bars, and are provided-with holes to receive the plug G for the purpose of connecting any two wires. Most of these last are used to connect subscribers win-sot the same group or table; but when there are two or more groups or tables in the same or different offices connected by trunklines, as shown in Figs. 5 and 6, we reservea suliicient number of these bars--say Nos. 1, 2, and 3-and connect them with corresponding bars on other tables by trunk-lines U U U, 850., in a manner and for purposes to be described hereinafter or, if preferred, the trunk-lines -U, U, and U can be connected with the tubes T in the same manner as subscribers wires, when connections can be made as desired, in the regular way, through plates P. Each of the bars or plates P is provided with a key, K, which, on being depressed, makes contact with the battery strip or plate P, for the purpose of ringing the belief asubscriber in case he does not answer promptly after he has been connected, and without disconnecting for that purpose.

A A are transmitters located conveniently at each corner ot' the table-one for each operator, say. The receivers are shown in Fig. 5. We have shown a table suitable for four open ators, located one on each side of the table.

Each one of these operators can reach and make any connections upon the whole table. The number of plates P used by us is thirtytive on each side for the connections of four hundred-subscribers. This number may be increased, as required by increased calls for connections, by making them narrower, placing them nearer together, or cutting them up into sections. Eachoperator is supposed to have, for convenience, a receiving-instrument secured to the head and ear, 'so as to leave The terminals and connecting-bars are ar.

IIO

ranged in a horizontal plane on the top of a button is table adapted to the convenient approach of the operators from all sides, and-we consider this the best arrangement; but we are aware that slight changes'may be made in the relak tions of the bars to the top of the table by a variation from the horizontal-toe considerableextent, but not without detriment to the We are by this means able to place the operators on different sides of the board, more or less facing each other, and consequently in positions to avoid mutual interference during manipulation. It

is evident that two operators may be placed opposite each other at such a board or table, and also that the table may even be made more than four-sided and adapted to more than fouroperators,ifdesired, without going beyond the scope of our invention. So, also, as to thelocation of the terminals in the center of the board. We are aware that the rel instruments and apparatus of two subscribers of each central office, are shown. The four subscribers instruments and apparatus are shown in what may be called the normal state, with the receiver on the hook and the switches under the control of their several springs.- In this conditionthe circuit of the subscribers signal or calling wire, which has the instruments of the subscribers listeningoperators 0 in circuit at the central office, passes through each one of the subscribers switches by way of the upper bar, which is continuous across theswitch, and therefore this circuit is without resistance, normally, outside of the central ofli'ce, except such as is offered by the line itself. .In the same condition the circuit ofthe subscribers or private wire,each one, starting from thetube T of the table at the central office, passes to that bar of the switch on the side approached which lies longitudinally, and thence by way of the line D, the receiver-hook lever, the line E, theopposite longitudinal bar, (the two being separated or insulated from each other,) by way of the bell-helix, to the ground. In this condition of the parts the telephone-instrumen ts and battery are cut outof the privatewire circuit; but when the receiveris lifted from its'hook the contact of the hook-lever with Ithecontact-point of the line I brings them into-the private or subscribers wire,. and in this condition of lines, apparatus, and

circuits the conversation between subscribers can be conducted. When, however, the pushswitch, and the circuit goes direct to the bell and ground, thus still providingfor calling the subscriber from the central otfice by ringing his bell. At the same time the vtelephone-instruments and battery are thrown or switched into the signal or call-line circuit, which then passes by Way of one of the upper springs, the longitudinal bar of the switch on one side the wires D, F, L, and H taking in the secondary coil of the transmitterand the telephone-instruments, and "passing out at the other upper contact-spring to the calling or subscribers wire beyond, and the local-battery-circuit being closed through the primary coil of the transmitter by way of the wires I,

.F, and J.

The method of operation will then be as follows: The operator, receiving the order, say, .to connect 12L with 22L by the signal-wire and touching the plugs to the nearest plate 1?. He

will then connect those subscribers lines (121.

.221) by inserting both plugs into any one of the plates P reserved for local connections and not in use. When the order to disconnectis received from either 121 or 221, the operator removes the plugs from the plate P and, giving each a touch to one of the battery-plates 1 sends signals-one to each party-over their private wires, that their-lines are disconnected. Each treceivirig-instrument having a difi'erent'set cf subscribersofficeson the signal-wire with which itis connected,it may be that the order to disconnect may not come to the operatonwho made the connection, since the party first called -for,and not the calling party, may give the disconnect order, but may come to either of the other operators sitting around the table,

or rather will come to the operator on whose signal-wire the subscriber giving the order is located. On receiving this order, being able to reach the entire table, either ofthe opera-t tors can readily execute the order. Both the connections and the disconnections are made in silence, and in obedience to'orders received at the ear of the one operator and without the knowledge of the others. By bringing the private wires to ground-plates or conductors directly, without any resistance or instruments causing resistance in the same, many advantagesare obtained. Its functions are to carry off atmospheric electricity, to permit the escapeof induced currents, to take a batteryeircuit from a cross or accident and prevent the ringing of the subscribers bells, and to accomplish other manifest advantages. Formerly the practice was to repeat the disconnect order over the signal-wire from the central office to the subscriber, thereby giving the subscriber notice of disconnectionas well as the switchboard operator who disconnects. The tendency of this practice in large exchanges may "be to overloadthe signal-wire with .work, while the private wire is idle; but by tapping the plug upon the battery-plate, as above mentioned, a bell is rung in the subscribers office through theprivate wire, thus relieving the signal-wire ofa part of its work, and saving all talking back of the listening-operator, who is consequently also relieved of a part of his former labor, and materially increasing the amount of work that can be done by the apparatus and a given number of operators.

S S are switches substantially like those shown in the Letters Patent of Frank Shaw, previously referred to. Three of the switches S keep the several receiving-instruments in circuit with the subscribers signal-wires; but

whiclrconnects with the group to which the desired number belongs, and requests the operator there,0, to connect, say, No. 3 with No.

1, by saying: "Connect 3 with 1," or "Three one, which being done, after the usual signal" to No. 3, the two subscribers will be found in connection through line U, which connects the two trunk-line bars No. 1 for conversation. The order to disconnect may be sent in the usual manner throughthe operator first called by No. 2, and through him to the operator 0,

who received the order to connect No. 3 with' No.1; or, if this order comes from No.3 to any operator at the group or table to which No. 3

belongs,-the status is evident at a glance, and. the ordcris sent to the group or table to which No. 2 belongs through the operator 0 on the trunk-signal wire X, and executed inthe usual'way, (X or X, according to the group from which the order emanates.) X, which, beginning'at the ground G at the left, passes into the switch S near the operator O of the upper side of thegroup No. 1, or table,'Fig. 5, also passes into the switches S near the other two operators 0, and also into the switch near the operator 0 of the same group,though this is not essential, as will appear further on. It will, be observed that it enters and passes out' at the bottom part of each one of these switches, but on reaching the switch S of the group 'No. 2, near the operator O of that group, enters that switch and emerges to ground at its top.- This'-arrangement enables any one of the three operators O of group No. 1 to signal and commu-;

nic'ate with the operator 0 of group No. 2 by simply depressing his switch-button and throwing his instrument into the circuit X X, and

The line X thus without disturbing either the two other operators 0 or the operator 0 of group No. 1. The line X X; of group No. 2 connects the switches and operators 0 of that group with the operatorO of-group No. 1 in a similar manner. The operators 0 of both groups receive and execute the trunk-line connection and disconnection ordersof the other group.

It will be'seen that each trunk-line operator 0 has for his duty only to receive orders for trunk-line connections from other central offices or other tables similarly connected. These trunk-signal lines will each pass from the out;- fit instruments of the operator Oof each office or table into the other offices or to other tables, and in such connection with the switches of each additional table that any one of the subscribers operators of any table may switch into any one'of such trunk-signal lines and give orders for trunk-line connections. The object of this arrangement is to direct only such orders as are to be filled by him to each trunk-line operator 0, and thereby relieve him from any necessity of listening to or hearing orders for other operators and selecting those intended for himself. Bythis means evidently the operator 0 can receive orders for and make a much larger number of connections than he otherwise could, which has thus become his sole function; and one operator receives the orders for trunk-lineconnections from all the other officesor tables, thereby keeping down the number of such operators, reducing expense, and promoting accuracy and dispatch of business. In case any operator 0, on receiving an order for a connection, finds that it cannot be executed for any reason, he can notify theoffice or table from which the order emanates of the fact, even after the. operator giving the order has switched his instruments out of the line, by'switching his outfit outof the line (X X or X, as the case may be) over which the ordercame andinto the line through which the subscribers operators 0 of his table transmit theirtrunk-line orders, such line being takenthrough the switch of the operator '0 for that purpose; and the notice is received by the trunk-line operator on that line, who

can either tell his associate subscribers operators, viva coca, the fact, leaving it to the, proper one to notify the subscriber calling for connection, or the trunk-line operator, glancing at the trunk-line bar engaged in his table for that connection, can himself signal directly-to the calling subscriber by auy specific number of taps on his v.bell, or in any ordinary manner; but this last-mentionedarrangement may be omitted.

The table-top is about thirty-two (32) inches square, and can be reached at all points by any IIO one of four operators sitting around it. We

have been able to place and operate four hundred 100) lines and circuits in one table. When the number of wires centering in one group is toolarge for one table, we provide another table of a similar construction, connected by whether these: additional 1 groups on tables are.

in the same room or officeor' located at a distance, the connectingapparatus between them isthe same, operation. i As shown, the rods ItRare solid,.and operateby their weight, so as to drop withinthe tubes automatically when the=plugsG G are withdrawn from the plates P and. released, the broad part: of theplugsG being drawn down thereby' ontothe ground-plates P, thus maintaining a normalground-connection when.- the several lines arenot in use for converse tion between subscribers; but in whatever position the rodimay be, the electrical circuit .connectingwith the tube and its lineis always complete through the German-silver spring S We are aware that a continuous contact may be efl'ected by any other usual; means for securing proper rubbing pressurexbetweeh the rod and the tube, but have found the light spring shownmost satisfactory. We conte'mplate'the use of a rubber strip or a spiral or. other spring, instead of the weighted rodsIt, to draw the contact-:sprin gs and the flexible cordsautomatically into the tubes T, with the. plug Gr bearing upon the ground-plate P, as described; and we do not desire to limit ourselves to the use of the tubes T1 and rods R standing upright, since it is evident that they may be placed horizontally and still be made to operate and effect very great economyof space, especially where the number of connections may not be so great as to require more than one operator.

It isievident' that the relationsbetween the tube T and the rod It may be reversed, The

rods willthen be stationary and in contact with the subscriberswires in the plank B,and the tubes will be movable, attached to the flexible cords, and capable of performing the functions of therodsin a similar manner; or one or more rings may be substituted for the tube, moving up and down-on the rod under the control of a weight or of a spring; orany other usual form of guide may be substituted tocontrol the movement of the circuit-maintaining spring or other device. We alsocontemplate the substitution of a permanent connection betweeneach subscribers wire in the plank B and the flexible cord D by means of. a.

spiralspring attached in any usual manner to each. The spiral spring would then act both.

as a spring to automatically withdraw the cord and plug and also as part of the circuit. {Dhese springs may be made movable in tubes made of wood or other suitable material, or held and kept separate from the adjoining springs by any usual kind of guides.

Our system of numbering the. subscribers i wires and plugs is as follows: Each one of the four plates P contains one hundred plugs. That to the left contains the one hundreds, the next to the right the two hundreds, the next'the three hundreds, and thenext the four trunk lines, as show'n in Figs. 5 and 6, and, hundredsi l'any numbencan be found instant] y. Each one ofithese sub-groups or sections has on each of their four sidesnumbers, as shown, from 0 to 9, and solikewiseis the method of.

Each-hundredbeingthus grouped,

opposite each row of ten holes. Consequently :the eye and hand of the operator instantly recognize the location of theplugot' any subscriber and subscribers wire, and he may therefore make the connections and d scounections instantly, since the operators sitting upon either side of the table can easily follow the decimalarrangement of the plugsbetween l and 100 in each section.

is the ground-wire of the trunk-signal line near the telephones of the subscribers operators outfit.

G? is the ground-wire of the subscribers call a line near the same.

G3 is the ground-wire of the trunk-signal line near theontfitof the trunk-signaloperator.

G is the ground of the plate P.

G is aground for the battery-plates]? P.

G is thegroundof the. subscribers ends of the subscribers calling-wire.

The several switches shown 1n the drawings are in themselves substantially alike, although they appear in two forms. In every instance the telephones andbattery-cell are connected to the twocenter contacts. In the switch having one coiled spring these contacts arethe two center flat springs, contact with the two insulated longitudinal barsof the switch. In the switch provided with two coiled springs these latter are used as parts of the lines on each side of the outfit, andconnect with the two longitudinal insulated bars, which are themselves movable in this instance by means of arms extending therefrom, to which the coiled springs are attached. We show in the drawings three distinct and separatecombinations of lines with this switch. Genetically the combinations are the same in =the'three; specifically they are different. The :first of these is like that found in the Shaw 1 patent, and is 'outfi-tsNos. 1,2, 3, andet. The second is shown in Figs. 1, 5, and outfits; and the third is shown in Figs. 5 and shown in Fig. (i-subscribers fi -subscribers operators 6trunk-signal-operators"outfits. 111 all the outfit is connected by the two center contacts with two insulated bars, and they are always in contact therewith, and two circuit-wires are brought to the two contacts at the two ends, one circuit to each, into one of which circuits the outfitis normally held by the coiled spring or springs, circuits the outfit may and into the other of which be thrown by simply pushing in the button. three cases theoutfit is normally looped into the private wire, and may be thrown, by moving the push-button, into the subscribers calling-wire; in the second the outfit is normally looped into the subscribers calling-wire, and may be thrown into thetrunk-signal wire; in the third the outfit is normallylooped into one of the trunk-signal wires leading from another and are constantly in In the first of these office or offices, table or tables, of the system to that one at which the trunk-signal outfit is placed to receive trunk-signals, and may be thrown, by moving the push-button. into the plates, in place of a battery and circuit-break. er, as shown.

We understand that such an arrangement would be equivalent to that shown in the drawings.

"We hereby disclaim,as far as this specifica tion and these Letters Patent are concerned,

all the inventions. shown, described, and

claimed or to be claimed in our original application No. 40,442, filed August 22, 1881, and not claimed herein, and this disclaimeris in favor of our said original application only.

' This disclaimer is intended to cover, and does cover, every invention not specifically claimed in the several claims of this specification, and

all inventions shown, described, or otherwise found herein and also found in the said original application, but not so claimed herein, are left in the said original application No. 40,442.

We claim as our invention- 1. In a-telephone-exchange system, a switching apparatus provided with the following elements in combination: first, a tube,T, or its equivalent, arranged to permit or facilitate a sliding electrical contact therewith second,

a conducting connection-cord, D, or its equivalent, arranged and provided at one end with devices to effect continuous sliding electrical contact with a tube, '1, or its equivalent, and at the other end with a plug and connection devices, substantially as shown and described.

2. In a telephone-exchange system, aswitching apparatus provided with the following elements in combination: a stationary tube, T, or its equivalent, forming the terminal of a subscribers line, a weighted sliding rod, R, and spring S, arranged to make and maintain automatically continuous sliding electrical contact between the tubeand rod, and flexible connections and switch-board plate, or their equivalents, substantially as shown and described.

3. In combination, the subscribers terminal, consisting of the tube T, the weighted sliding rod R, in frictional contact with the tube and a flexible connection, the groundsignal-plate P, as shown and described. v

4. In combination, the subscribers terminal, consisting of the tube T, the weighted sliding rod It, in frictional contact with the tube, and the ground-plate I.

5. In a switchingapparatus for a telephoneexchange, subscribers terminals consisting of tubes T T, weighted sliding rods It R, in fric- The current may be derived from .a

outfit normally tional contact with the tubes, and flexible con-- ;nections, in combination with one or more con-' nection-plates, P

6. In a'switohing apparatus for a telephoneexchange, subscribers terminals consisting of tubes T T, weighted sliding rods R R, in frictional contact with the tubes, and flexible connections, in combination with one or more connection-plates, P placed horizontally at right angles to the tubes.

7. A switching apparatus in a telephone-ex-i change, provided with subscribers terminals consisting of tubes T T, weighted sliding rods It It, in frictional contact with the tubes, and

flexible connections, one or more ground-plates, P, one or more signaling-plates, P, one or more battery-plates, P P, and one or more connection-plates, P

S. In a telephone-exchange, a switch-table with four sides, having its subscribers terminals located or massed in or adjoining the center of the table, devices on each side of the same for subscribers or trunk lines.

9. In a telephone-exchange, a switch-table with four sides, having its subscribers terminals located or massed in or adjoining the center of the table, and one or ing devices for signaling on each side of the same for signaling subscribers.

10. Ina telephone-exchange, a switch-table with four sides, having its subscribers termi-.

nals located or'massed in or adjoining the center of the table, and its connection and signaling plates on each sideof the same..

11. In a telephone-exchange, a four-sided switch-table having its subscribers terminals located or massed in or adjoining the center of the table, the connection and signaling plates on each sideof the same for subscribers and trunk lines, and at the corners of the table an operators outfit, wherebythe operator may receive orders for connection and disconnection and execute the same.

12. In a telephoneexchauge system, a trunksignal line consisting of a line extending between two central offices for giving and receiving signals for connections and disconnections between two central offices, a subscribers signal-line consisting of a line extending between a subscribers station and a central station for giving and receiving signals for connections and disconnections between sub scribe-rs, provided with a listening-operators located in the subscribers sig= nal-line, and a switch combined and arranged to switch the operators outfit at will from the subscribers signal-line into the trunk-signal line.

13. In a telephone-exchange system, a sub scribers signal-line consisting of a lineextending between a subscribers station and a central station, for giving and receiving signals for connections and disconnections, trunk-signal lines consisting of lines extending between two central offices, one for giving and another,

and its series of connecting.

more circuit-closfor receiving signals for connections and disconneotions between two central oflices, provided with a listening-operator's outfit, normally located in one trunk-signal line, and a switch combined and arranged to switch the operators outfit at will from that trunk-signal line into another trunk-signal line.

let. The combination of the connection-plates P, the battery-plate P and keys K, for the purpose of ringing the subscribers bell after connection of two subscribers has been made, and without disconnecting the same.

15. In combination, a ground-plate, P, and a automatically-operated plug, Gr, brought into ing any two subscribers lines, which are automatically withdrawn below the table-top when the subscribers lines are disconnected.

18. In a telephone-exchan ge switch-board and apparatus, the following elements in combination: first, a table with horizontal top second,

I the central-oflice ends of subscribers lines, en-

tering the table from below and terminating in the table-top; third, automatically withdrawn ,connecting-cords and apparatus; and, fourth, call or signal wire and'operators outfit for receiving orders to connect and orders to disconnect, located beside and within reach of the sub scribers lines, terminals, and connecting-cords.-

19, In a telephone-exchange system, atrunksignal wire, consisting of a line extending between two or more (a series of) central oftices or tables, provided with an operators outfit, located in the trunk-signal line at one of the central offices of the series only, and provided at each of the other centraloffices with one or more switches,(one for each operator,) arranged to switch the outfit (one or more) of one or more subscribers operators into the trunk-signal line,.for the purpose of transmitting orders for connection and disconnection to one central office from all the others of the series.

20. In a telephone-exchange system, subscribers wires normally grouped and brought directly toone or more common ground-plates or conductors, without theintervention of an- 1 nunciator, telephone, or other coils or devices offering resistance to theelectrical current on or in the wires between the central office common'ground-plate or conductor and the subscribers offices.

21. In atelephone-exchange system provided with a call-wire and with an independent private wire, the call-wire provided with a subscribers operators outfit at the central office, and the private wire provided with batteryplate for signaling to the subscriber in reply to a call for connection or disconnection, as shown, or its equivalent.

FRANK SHAW. WM. A. OHILDS.

Witnesses:

JAMES A. SKILroN, W. H. ll/IAGINNIS. 

